Electronic devices of various kinds are well known. Moreover, each of these electronic devices includes elements that tend to heat up with use over time. For example, computing devices include processor circuits that will heat up over time and with increased use of the processing device as a result of the amount of current that flows through a circuit during its operation. The heating of the processing device is a known artifact in the computing world. For example, certain computing devices such as large desktop computers include temperature protection mechanisms such that the processing device or other components of the system do not overheat and break down.
Accordingly, in certain applications, temperature sensors are incorporated into computing devices to sense the temperature of certain components that are susceptible to break down or failure as a result of overheating. For example, an infrared heat detector can be disposed to collect infrared energy given off by a heated portion of the device. The infrared sensor collects that infrared radiation and converts it into a voltage from which a computing device can determine the temperature of the material from which the heat sensor is collecting infrared radiation. In one example, a heat sensor includes a thermopile or a component whose electrical properties (such as voltage) change when the temperature gradient across the component changes. So configured, one end of the thermopile is configured to be heated by the infrared radiation received from the material of which the temperature is to be sensed. This side is called a “hot junction” of the thermopile. The other side of the thermopile is called a “cold junction” and is kept at a relatively stable temperature such that changes in temperature of the first side of the thermopile or “hot junction” will result in a change in the electrical properties of the thermopile that can be tracked and correlated to temperature of the target material.
It is known, however, that during a thermopile's hot junction temperature change, the temperature determination of the target material will be inaccurate. This is because part of the heat flow on the thermopile's hot junction is used to change the temperature of the hot junction rather than generate the signal. Once the temperature is stable then this error disappears. The major source of temperature change of the hot junction in an infrared sensor is through heat transfer to and from the cold junction. As a result, infrared sensors designed to be placed into computing devices, for example, are designed such that sensor itself or at least the cold junction is as thermally isolated from the remaining system and computing device as possible so as to reduce temperature changes that could result in temperature sensing errors. By configuring the infrared sensor in this manner, the infrared sensor itself has a relatively bulky size and takes up a relatively large amount of space which can be detrimental when implemented in a computer or other mobile electronic device or size and portability device can be a high priority or concern. Moreover, thermal isolation only partially mitigates the errors introduced during temperature variations because the thermal isolation is not perfect.